Organophosphorus compounds containing n-bonded pyrrole groups

ABSTRACT

DISCLOSED HEREIN ARE COMPOUNDS OF THE FORMULA   (R&#39;&#39;-PYRROLO)Y-P(=A)X(-(O)M-R)Z   WHEREIN: A=O OR S R&#39;&#39;=H OR LOWER ALKYL R=SUBSTITUTED UNSUBSTITUTED HYDROCARBYL GROUPS OF UP TO 12 CARBONS X=O, 1 M=0, 1 Y=1, 2 Z=1, 2 Y+Z=3; AND A PROCESS THEREFOR CONPRISING REACTING AN ALKALI METAL PYRROLE WITH THE APPROPRIATE HALOPHOSPHROUS REACTANT AND, WHEN X=1, REACTING AN OXYGEN OR SULFUR OXIDANT WITH THE PRODUCT OF SAID REACTION.

United States Patent "ice ffi $11 .3

SUMMARY OF THE INVENTION sg g g C0NTAIN This invention concerns novel compounds of the for- ING N-BONDED PYRROLE GROUPS mula Joseph J. Mrowca, Wilmington, Del., assignor to E. I. du

Pont de Nemours and Company, Wilmington, Del. 5 No Drawing. Filed Jan. 25, 1972, Ser. No. 220,705

Int. Cl. C0711 27/20 U.S. Cl. 260--326.61 30 Claims 7 ABSTRACT OF THE DISCLOSURE 10 wherein:

Disclosed herein are compounds of the formula A=O or S R'=H or lower alkyl (A), R=hydrocarbyl of up to 12 carbons; or aliphatic hydro- Lll R)- 15 carbyl of up to 12 carbons substituted with fluorine, m CF or OR", Where R" is aryl of up to 10 carbons or lower alkyl; or aromatic hydrocarbyl of up to 12 carbons substituted with halogen, CF or OR"; and wherein: Where the R groups can form a hydrocarbyl diradical A==O or s when Z is 2 R'=H or lower alkyl 26 1 R=substituted or unsubstituted hydrocarbyl groups of up to 12 carbons x=0, 1 z=1, 2 and m=0, 1 Contemplated diradicals formed from the R groups in y=1, 2 the generic formula (where z is 2) include but are not 2:1, 2 limited to the following: y+z= and a process therefor comprising reacting an alkali metal 30 CH: pyrrole with the appropriate halophosphorus reactant and, f when x=1, reacting an oxygen or sulfur oxidant with T T CH (when and (when m 1)' the product of said reaction. a

Preferred compounds of this invention are those in BACKGROUND OF THE INVENTION which R is alkyl, alkenyl, aryl, alkaryl, and aralkyl, in- (1) Field of the invention eluding substituted alkyl, alkenyl and aryl. It is also preferred that when z=2, the two R. groups be in the form This invention relates to organophosphorus compounds of a diradical.

contammg N'bonded pyrrole groups 40 Especially preferred compounds are those in which R (2) Description f the prior art is alkyl and alkyl substituted with OR", aryl and aryl substituted with CH or F, and R is H.

Although a number of dlfferent types of e The substit-uents on the R groups, as will be appreciated, bonded Phosphorus compounds are known those f should be nonreactive with the alkali metal pyrrole comillg a Py group bonded to P P descllbe'd by pounds. Those skilled in the art will understand that there this inventi n are W- II! the known I11tFge11'b9I1def1 are other substituents than those specifically noted here- PhOSPhOIUS Compounds, the nitrogen-Containing molety 15 in which will not react with the pyrrole compounds. All other than py example, it is known that Such of such substituents are within the scope of this invention. aromatic and alicyclic amines as tetrahydroquinoline and B h d b l i meant a di l d i d from a Piperidine give N-sllbstituted Phosphines with 3 and hydrocarbon by removal of a hydrogen atom. The radical With diehlorophenyiphosphine lMiehflelies, Chem- Bel can be saturated or it can contain olefinic or acetylenic 31 1037 A1111 129 unsaturation provided that the acetylenic unsaturation is Ch m. Bell, 1042 Likewise, iIldOle 3111011 is not due to terminal acetylenic bonds. The term hydroknown to give N-substituted products with POCl and b l i l d u alkaryl o lkyl Wi h PC13 [Miflg0i3, GaZZ- Chim- Ital 4 (1930); 5 groups, cycloaliphatic groups, alkyl groups, alkenyl groups ibid., 62, 333 (1932)]. and non-terminal alkynyl groups. The term lower alkyl When the nitrogen-containing moiety is py the means alkyl groups having up to 6 carbon atoms.

art teaches that the bond between Said m iety a d a P S- Process-This invention also concerns the process for phorus-containing moiety will be a carbon-phosphorus making th el compounds, where x=0, comprising bond- T1181t the py anion gives eafbomphosphoflls 50 reacting an alkali metal pyrrole reactant with the apdS Was found y Mingeia, ibidq 62, 333 propriate halophosphorous reactant according to the re- Issleib-et al., Z. Anorg. Allg. Chem., 292, 245 (1957); ti

and Grifiin et al., J. Org. Chem., 30, 91 (1965).

On the basis of the art it is unexepcted that the rey 6 N Alkali Halogen P((O)mR). action products of pyrrole anion with the disclosed trimetal valent organophosphorus compounds would have N- R bonded pyrrole groups The novel products disclosed herein are further distinguished from the C-bonded prodwherein R, R, m, y and z are as defined above and whereucts of the art by their lack of reactivity associated with in the halogen is preferably chlorine or bromine and the an N--H bond. For example, they do not form a potas- 7O alkali metal is preferably potassium.

sium or magnesium bromide derivative as do pyrroles The novel compounds wherein x-==l and wherein there with hydrogen attached to nitrogen. is an oxygen or sulfur atom doubly bonded to the phosphorus are made by reacting the trivalent phosphorus compounds (made, in sequence, as described above) with an oxidant selected from the group consisting of oxygencontaim'ng oxidants and sulfur-containing oxidants. Reaction of the pyrrole with the halophosphorus reactant is followed by reaction of the trivalent phosphorus reaction product with an oxidant as described.

4 DETAILS OF THE INVENTION Various specific compounds representative of all the products within the scope of this invention are shown below in Column III. The compounds are made according to the process herein described by reacting the alkali metal pyrrole of Column I with the halophosphorus reactant of Column II.

Same as above. BrP (CH9 0.11;

N-P (CH1) CsHi Same as above..:. C1zPOCHzC|H| Column I Column II Column III F 6 N K OlzPQ-OCaHi N P -0CaHa LQJ i=/ /2 Same as above.... 01 PC H 2 N- PCaH Do C1PCH=OHC3H 2 N PCH=CHCaH1 Do Cl2POCH2CH=CHn NPOCHzCH=CH2 Do- C1P(CH=CH:)2

N-P (CH=CH2)2 Do CIP(CH;CH=CH) N-P(CH2OH=CH2):

Do CH\2 /CH\ CIP N-P CH2 CH2 DO CIP 00 H) H I fv-Pwoun D0 C1P(CaHs)z wHm ClP-CuHa (HwHm H: i e N K69 N-lF-CuHs one Br Br 9 N 11 (Di- 6 Same as above C1P(CHzOEOCHa)2 NP(CHCEC CH1):

(DIP-Q0 CH3 NPO OH;

Do C1P(CHzCHa)2 2CHQM The corresponding phosphine oxides and phosphine where A=S. In each case, when a trivalent phosphine in sulfides (x=1, A=O or S) are readily prepared from Column III is so treated, the corresponding phosphine the trivalent phosphorus compounds of Column III by 7 oxide or phosphine sulfide is obtained. For the purposes reaction with an oxygen oxidant or a sulfur-containing of this invention, as will be understood by those skilled in oxidant, respectively. Preferred oxidant reagents include the art, phosphine oxides are chemically equivalent to hydrogen peroxide, oxygen, air, nitric acid, mercuric the corresponding phosphine sulfides. oxide and chromic acid for preparing compounds where Rather than depict all the pentavalent phosphine oxides A=O, and elemental sulfur for preparing compounds 75 and sulfides corresponding to the trivalent phosphines of Column III above, for the sake of brevity, only several will be specifically set out (although all are meant to be included):

H N-Il. 02115):

NH n-butyl Li NH NaH halophosphorus e N Li compound N -bonded phosphorus compound compound N-bonded phosphorus compound Normally, reaction between alkali metal pyrrole deriva tives and halophosphorus compounds is carried out in an ether-type solvent. Examples of such solvents include diethyl ether, diisopropyl ether, di-n-butyl ether, di-n-amyl ether, tetrahydrofuran, dioxane, Z-methoxyethyl ether (diglyme) and 1,2-dimethoxyethane (glyme).

Reaction temperatures used in the preparation of the trivalent phosphorus compounds normally range from -20 C. to +50 C. with the preferred temperature range from 0 to 25 C. The reaction pressure is in the range of 0.5 to 1.5 atmospheres, but the reaction is most conveniently carried out near atmospheric pressure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples are meant to illustrate but not to limit the invention. NMR spectra were obtained in deuterated chloroform solution with tetramethylsilane as internal standard. Nitrogen-phosphorus bonding was established by infrared and proton NMR data. The infrared spectra of the products are devoid of v vibrations in the 3400 cm.-1 region characteristic of pyrrole N--H bonds [C. E. Griffin, R. P. Teller, and I. A. Peters, J. Org. Chem, 30, 91 1965)]. The proton NMR spectra give integrations, 10:2:2 or 12:2, that are consistent only with nitrogen-bonded products.

EXAMPLE 1 Diphenoxy 1-pyrryl)phosphine CHO P-N (at):

A solution of 50 g. of diphenylphosphorochloridite in 200 ml. of ether was added dropwise to a stirred, icecooled mixture of 22 g. of pyrrylpotassium in 500 ml. of ether under nitrogen. The mixture was stirred for 3 days, filtered, and the filtrate was evaporated under vacuum.

The residue was distilled through a spinning band column to give 24 g. of diphenoxy(1-pyrryl)phosphine as a clear liquid, B.P. 120-123" C. at 0.1 mm.

Anal. Calcd. for C H NO P: C, 67.83; H, 4.98; P, 10.93. Found: C, 67.48; H, 4.90; P. 10.90.

NMR: 1- 2.5-3.2 m (12 H) aromatic -g and N011, 'r 3.64 t (2 H) NCH=CE.

IR (neat): No 11 in spectrum.

EXAMPLE 2 Diphenyl l-pyrryl) phosphine A solution of 50 g. of chlorodiphenylphosphine in 200 ml. of ether was added dropwise to a stirred, ice-cooled supension of 25 g. of pyrrylpotassium in 500 ml. of ether under nitrogen. The mixture was stirred for 18 hours, flltered, and the filtrate was evaporated under aspirator vacuum. The residue was distilled through a spinning band column to give 32.5 g. of diphenyl(l-pyrryDphosphine as a clear liquid, B.P. 120123 C. at 0.1 mm.

Anal. Calcd. for C H NP: C, 76.48; H, 5.61; N, 5.57; P, 12.32. Found: C, 76.25; H, 5.54; N, 5.29; P, 11.83.

NMR: 1- 25-30 m (10 'H) aromatic -g, 'r 3.16 m (2 H)NC 11, 1- 3.68 t (2 H) NCH=C.

IR (neat): No u observed.

EXAMPLE 3 Diphenyl(1-pyrryl)phosphine oxide To a stirred, ice-cooled solution of 10 g. of diphenyl(lpyrryl)phosphine in m1. of acetone was added dropwise 4.8 g. of 30% hydrogen peroxide. The mixture was stirred overnight, evaporated under vacuum, and the residue was recrystallized from 400 ml. of cyclohexane to give 8.1 g. of diphenyl(1-pyrryl)phosphine oxide as white crystals, MJP. l20121 C.

Anal. Calcd. for C H NOP: C, 71.90; H, 5.28. Found: C, 72.04; H, 5.30.

NMR: 1- 2.5 m (10 H) aromatic -11, 1- 3.12 m (2 H) Neg, T 3.4 t 2 H) -NCH=I IR (Nujol): No v observed, U o=1220 cmf comm-N 2-( l-pyrryl) -l,3,2-dioxaphospholane P 01 e K+ K01 Ethylenephosphorochloridite (50 g.) was added dropwise to a stirred suspension of 41.5 g. of pyrrylpotassium in 400 ml. of ether under nitrogen. The mixture was stirred for 18 hours, filtered, and the filtrate was evaporated under aspirator vacuum. The residue was distilled through a spinning band column to give 41.2 g. of 2-(1- pyrryl)-1,3,2-dioxaphospholane as a clear liquid; B.P. 88-90 C. at 5 mm.

Anal. Calcd. for C H NO P: C, 45.89; :H, 5.09; P, 19.73; N, 8.91. Found: C, 45.70; H, 512; P, 19.16; N, 9.06.

NMR: 1- 3.12 m (2 H) NOE, 'r 3.68 t (2 H) NCH=C, 'r 5.8 m (4 H) Cg IR (neat): No u in spectrum.

EXAMPLE 5 Diphenyl( l-pyrryl)phosphine sulfide A mixture of 0.65 g. of sulfur, 5.0 g. of diphenyl (1-pyrryl)phosphine, and 30 ml. of benzene was refluxed under nitrogen for 1 hour and then stirred at room temperature for 1 day. The resulting clear, colorless solution was evaporated under vacuum, and the residue was recrystallized from 75 ml. of cyclohexane to give 3.65 g. of diphenyl(l-pyrryl)phosphine sulfide as White crystals, M.P. 108110 C.

Anal. Calcd. for C H N-PS: C, 67.82; H, 4.98; N, 4.94; P, 10.94. Found: C, 67.41; H, 4.99; N, 4.74; P, 10.70.

NMR: 7' 2.5 In H) phenyl H, 1- 3.01 m (2 H) NC I;I ,1- 3.58 m (2 H) NCH=C.

IR (KBr): No v in spectrum.

EXAMPLE 6 Diethoxy( l-pyrryl) phosphine A solution of 65 g. of diethylphosphorochloridite in 250 ml. of ether was added dropwise to a stirred, icecooled suspension of 50 g. of pyrrylpotassium in 500 ml. of ether under nitrogen. The mixture was stirred overnight, filtered, and the filtrate was evaporated under vacuum. The residue was distilled to give 60 g. of diethoxy- (l-pyrryl)phosphine as a clear liquid, B.P. 3842 C. at 0.1 mm.

Anal. Calcd. for C H NO P: C, 51.33; H, 7.53; N, 7.48; P, 16.56. Found: C, 51.09; H, 7.29; N, 7.17; P, 16.06.

NMR: 1' 2.95 m (2 H) NCH, 1- 3.67 t (2 'H) NCH=CE, 1- 6.13 m (4 H) OCH 'r 8.77 t (6 H) CH IR (neat): No v in spectrum.

EXAMPLE 7 'Phenyldi( 1-pyrryl)phosphine A solution of 50 g. of dichlorophenylphosphine in 200 ml. of ether was added dropwise to a stirred, ice-cooled suspension of 70 g. of pyrrylpotassium in 500 ml. of ether under nitrogen. The mixture was stirred overnight, filtered, and the filtrate was evaporated under vacuum to give 52 g. of phenyldi(l-pyrryl)phosphine as a white solid, M.P. 45-51 C.

Anal. Calcd. for C H N P: C, 69.98; -H, 5.45; N, 11.66; P, 12.91. Found: C, 69.63; H, 5.50; N, 11.26; P, 12.30.

NMR: 7' 2.5-3.2 m (9 H) phenyl -l.[ and NCI 'r 3.65 t (4 H) NCH=CH.

IR (Nujol): No u in spectrum.

EXAMPLE 8 Phenyldi(1-pyrryl)phosphine oxide To a stirred, ice-cooled solution of 5 g. of phenyl-di(1- pyrryl)phosphine in 50 ml. of acetone was added drop- Wise 2.7 g. of 30% hydrogen peroxide solution. The mixture was then stirred for 1 hour at room temperature and filtered. The filtrate was evaporated under vacuum, and the residue was recrystallized from 150 ml. of cyclohexane to give 2.6 g. of phenyldi(1-pyrryl)phosphine oxide as white crystals, M.=P. 93-95 C.

Anal. Calcd. for C H N OP: C, 65.61; H, 5.11; N, 10.93; P, 12.10. Found: C, 65.51; H, 5.07; N, 10.59; P, 11.72.

NMR: 1- 2.5 m (5 H) phenyl 1 -r 3.14 m (4 H) NCE, 7' 3.58 m (4 H) NCH=CE.

IR (KBr): No u in spectrum.

10 EXAMPLE 9 Diethoxy 1-pyrryl)phosphine sulfide (CHaCH OhP-N A mixture of 1.75 g. of sulfur, 10 g. of diethoxy(1- pyrryl)phosphine, and ml. of benzene was refluxed under nitrogen for 4.5 hours. Volatiles were removed from the clear, colorless solution under vacuum, and the residue was distilled to give 10.12 g. of diethoxy(1-pyrryl) phosphine sulfide as a colorless liquid, B.P. 60-63 C. at 0.05 mm.

Anal. Calcd. for C H NO PS: C, 43.82; 6.43; N, 6.38. Found: C, 44.09; H, 6.30; N, 6.10.

NMR: 1 2.83 m (2 H) NC H 7' 3.65 m (2 'H) NCH=C H, 1- 5.86 m (4 H) CH2, 1' 8.70t (6 H) CH IR (neat): No u in spectrum.

EXAMPLE 10 1-pyrryldi(p-methylphenoxy) phosphine A solution of 50 g. of chlorodi(p-methylphenoxy)phosphine in 200 ml. of ether was added dropwise to a stirred, ice-cooled suspension of 21 g. of pyrrylpotassium in 300 ml. of ether under nitrogen. The mixture Was stirred at room temperature overnight, filtered, and the filtrate was evaporated under vacuum. The residue was distilled through a spinning band column to give 41 g. of l-pyrryldi(p-methylphenoxy)phosphine as a clear liquid, B.P. 137-140" C. at 0.05 mm.

Anal. Calcd. for C H NO P: C, 69.44; H, 5.82. Found: C, 69.44; H, 5.84.

NMR: 1' 3.0 rn (10H) phenyl H and NCE, 'r 3.63 t (2 H) NCH=C I1, 1- 7.73 s (6 H) CH IR (neat): No v in spectrum.

EXAMPLE 1 1 l-pyrryldi (p-fluorophenoxy) phosphine A solution of 32 g. of chlorodi(p-fluorophenoxy)phosphine in 150 ml. of ether was added dropwise to a stirred, ice-cooled suspension of 14 g. of pyrrylpotassium in 150 ml. of ether under nitrogen. The mixture was stirred overnight, filtered, and the filtrate was evaporated under aspirator vacuum. The residue Was distilled through a spinning band column to give 24 g. of 1-pyrryldi(p-fluorophenoxy) phosphine as a clear, viscous liquid, B.P. 110 C. at 0.5 mm.

Anal. Calcd. for C H F NO P: C, 60.19; H, 3.78; N, 4.38. Found: C, 60.48; H, 3.96; N, 4.40.

NMR: '1' 3.0 m (10 H) phenyl H and NCE, 1- 3.60 t (2 H) NCH=C.

IR (neat) No v in spectrum.

EXAMPLE 112 Diethyl 1-pyrryl)phosphine This reaction was run in a nitrogen box. To a stirred suspension of 10.0 g. of pyrrylpotassium in ml. of

ether was added dropwise 10.0 g. of diethylchlorophosphine. The mixture was stirred overnight, filtered, and the filtrate was evaporated under vacuum to give 11.2 g. of diethyl( 1-pyrryl)phosphine.

Anal. Calcd. for C H NP: C, 61.92; H, 9.09; N, 9.03. Found: C, 61.87; H, 8.53; N, 8.32.

NMR: 1' 2.85 m (2 H) NCE, q- 3.73 m (2 H) NCH =C ]1, 1- 7.9-9.4 m H) cg cg The product was purified by distillation to give 6.62 g. of product, B.P. 34 C. at 0.05 mm.

Anal. Calcd. for C H NP: C, 61.92; H, 9.09; N, 9.03. Found: C, 61.68; H, 9.14; N, 8.87.

Utility The novel compounds of this invention are useful as flame retardants for both cotton fabrics and wood. The examples below describe the use of several of these materials in these applications. The manner and result of flame proofing as set out in Examples A to H are representative of the manner and result of employing any and all of the novel compounds disclosed herein.

EXAMPLES A-D Flameproofing cotton A l-g. sample of diphenyl(1-pyrryl)phosphine (Example 2) was dissolved in 4 ml. of dimethylformamide and a strip of cotton cloth was soaked in the solution for minutes. The cloth was removed and allowed to air-dry olvernight. When a flame was applied to the cloth and then removed, the cloth was self-extinguishing. An untreated sample of the cloth continued to burn vigorously, even after the flame was removed. The organophosphorus compounds with N-bonded pyrrole groups described in Examples 7, 8 and 9 were tested in a similar manner and in each case the treated cotton became self-extinguishing.

EXAMPLES E-H Flameproofing wood In a similar way, a l-g. sample of diphenyl(l-pyrryl) phosphine (Example 2) was dissolved in 4 ml. of dimethylformamide and a small wooden stick was immersed in the solution for 15 minutes. The stick was removed and allowed to dry overnight. When a flame was applied to the stick and then removed, the stick was self-extinguishing. An untreated stick continued to burn vigorously, even after removal of the flame. The organophosphorus compounds with N-bonded pyrrole groups described in Examples 7, 8 and 9 were tested in the same manner and in each case the treated wood became self-extinguishing.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A compound of the formula (A) z N i ((0) 111B) I wherein:

A=0 or S when m=0, and

when m=1 x=0, 1 m=0, 1 y: 1, 2 z=1, 2 and y+z=3.

2. A compound according to claim 1 wherein x=0. 3. A compound according to claim 2 whereiny 1. 4. A compound according to claim 3 wherein m=0. 5. A compound according to claim 4 of the formula 6. A compound according to claim 4 of the formula 10. A compound according to claim 8 of the formula 11. A compound according to claim 8 of the formula 12. A compound according to claim 8 of the formula li b-Q0.

13. A compound according to claim 8 wherein R is a diradical.

14. A compound according to claim 13 of the formula 15. A compound according to claim 2 wherein y=2. 16. A compound according to claim 15 wherein m=1. 17. A compound according to claim 15 wherein m=0. 18. A compound according to claim 17 of the formula 19. A compound according to claim 1 wherein x=1. 20. A compound according to claim 19 wherein y==1. 21. A compound according to claim 20 wherein m =0. 22. A compound according to claim 21 of the formula 23. A compound according to claim 21 of the formula 24. A compound according to claim 20 wherein m=l. 25. A compound according to claim 24 wherein R is a diradical.

13 14 26. A compound according to claim 24 of the formula References Cited fi UNITED STATES PATENTS D 2,663,705 12/1953 Parker et a1. 260-239X 27. A compound according to claim 19 wherein y=2. 5 6/1969 Tolkmlth at 26o326 28. A compound according to claim 27 wherein m\=1. 29. A compound according to claim 27 wherein m =0. JOSEPH NARCAVAGE Pnmary Exammer 30. A compound according to claim 29 of the formula CL 

